Thin-film magnetic head with low barkhausen noise and floating-type magnetic head therewith

Abstract

A thin-film magnetic head includes a spin-valve thin-film magnetic element, first and second insulating layers, and first and second shielding layers. The spin-valve thin-film magnetic element includes a free magnetic layer, a nonmagnetic conductive layer, a pinned magnetic layer, an antiferromagnetic layer, a pair of bias layers, and a pair of conductive layers. The pair of conductive layers is located on one side in the thickness direction of the free magnetic layer, and the pair of bias layers is located on the other side in the thickness direction of the free magnetic layer, is disposed on both sides in the track width direction of at least a portion of the second insulating layer, and is in contact with the free magnetic layer.

What is claimed is:  
     
       1. A thin-film magnetic head comprising: 
       a spin-valve thin-film magnetic element comprising:  
       a free magnetic layer;  
       a nonmagnetic conductive layer in contact with the free magnetic layer, the nonmagnetic conductive layer being located on one side in the thickness direction of the free magnetic layer;  
       a pinned magnetic layer in contact with the nonmagnetic conductive layer;  
       an antiferromagnetic layer in contact with the pinned magnetic layer, the antiferromagnetic layer pinning the magnetization direction of the pinned magnetic layer;  
       a pair of bias layers for aligning the magnetization direction of the free magnetic layer; and  
       a pair of conductive layers for applying a sensing current to the free magnetic layer;  
       a first insulating layer and a second insulating layer each deposited on a side in the thickness direction of the spin-valve thin-film magnetic element; and  
       a first shielding layer and a second shielding layer in contact with the first insulating layer and the second insulating layer, respectively;  
       wherein the pair of conductive layers is located on one side in the thickness direction of the free magnetic layer, and the pair of bias layers is located on the other side in the thickness direction of the free magnetic layer, is disposed on both sides in the track width direction of at least a portion of the second insulating layer, and is in contact with the free magnetic layer, and  
       wherein the pair of bias layers is disposed on both sides in the track width direction of the second insulating layer, the pair of bias layers comprises an antiferromagnetic insulating material, and the second shielding layer is in contact with the pair of bias layers and the second insulating layer.  
     
     
       2. A thin-film magnetic head according to  claim 1 , wherein the antiferromagnetic insulating material is one of NiO and α-Fe 2 O 3 . 
     
     
       3. A floating-type magnetic head comprising a slider and a thin-film magnetic head according to  claim 1 . 
     
     
       4. A thin-film magnetic head according to  claim 1 , wherein the pair of conductive layers is located on both sides in the track width direction of the nonmagnetic conductive layer, the pinned magnetic layer, and the antiferromagnetic layer, and the pair of conductive layers is in contact with the free magnetic layer. 
     
     
       5. A thin-film magnetic head comprising: 
       a spin-valve thin-film magnetic element comprising:  
       a free magnetic layer;  
       a nonmagnetic conductive layer in contact with the free magnetic layer, the nonmagnetic conductive layer being located on one side in the thickness direction of the free magnetic layer;  
       a pinned magnetic layer in contact with the nonmagnetic conductive layer;  
       an antiferromagnetic layer in contact with the pinned magnetic layer, the antiferromagnetic layer pinning the magnetization direction of the pinned magnetic layer;  
       a pair of bias layers for aligning the magnetization direction of the free magnetic layer; and  
       a pair of conductive layers for applying a sensing current to the free magnetic layer;  
       a first insulating layer and a second insulating layer each deposited on a side in the thickness direction of the spin-valve thin-film magnetic element; and  
       a first shielding layer and a second shielding layer in contact with the first insulating layer and the second insulating layer, respectively;  
       wherein the pair of conductive layers is located on one side in the thickness direction of the free magnetic layer, and the pair of bias layers is located on the other side in the thickness direction of the free magnetic layer, is disposed on both sides in the track width direction of at least a portion of the second insulating layer, and is in contact with the free magnetic layer, and  
       wherein the second shielding layer is provided with a shielding protrusion protruding toward the spin-valve thin-film magnetic element, the second insulating layer is disposed between the shielding protrusion and the spin-valve thin-film magnetic element, the pair of bias layers is disposed on both sides in the track width direction of the shielding protrusion and the second insulating layer, and the pair of bias layers comprises an antiferromagnetic insulating material.  
     
     
       6. A thin-film magnetic head according to  claim 5 , wherein the pair of conductive layers is located on both sides in the track width direction of the nonmagnetic conductive layer, the pinned magnetic layer, and the antiferromagnetic layer, and the pair of conductive layers is in contact with the free magnetic layer. 
     
     
       7. A thin-film magnetic head according to  claim 5 , wherein the antiferromagnetic insulating material is one of NiO and α-Fe 2 O 3 . 
     
     
       8. A floating-type magnetic head comprising a slider and a thin-film magnetic head according to  claim 5 . 
     
     
       9. A thin-film magnetic head comprising: 
       a spin-valve thin-film magnetic element comprising:  
       a free magnetic layer;  
       a nonmagnetic conductive layer in contact with the free magnetic layer, the nonmagnetic conductive layer being located on one side in the thickness direction of the free magnetic layer;  
       a pinned magnetic layer in contact with the nonmagnetic conductive layer;  
       an antiferromagnetic layer in contact with the pinned magnetic layer, the antiferromagnetic layer pinning the magnetization direction of the pinned magnetic layer;  
       a pair of bias layers for aligning the magnetization direction of the free magnetic layer; and  
       a pair of conductive layers for applying a sensing current to the free magnetic layer;  
       a first insulating layer and a second insulating layer each deposited on a side in the thickness direction of the spin-valve thin-film magnetic element; and  
       a first shielding layer and a second shielding layer in contact with the first insulating layer and the second insulating layer, respectively;  
       wherein the pair of conductive layers is located on one side in the thickness direction of the free magnetic layer, and the pair of bias layers is located on the other side in the thickness direction of the free magnetic layer, is disposed on both sides in the track width direction of at least a portion of the second insulating layer, and is in contact with the free magnetic layer, and  
       wherein the pair of bias layers is disposed on both sides in the track width direction of the second insulating layer, the pair of bias layers comprises an antiferromagnetic insulating material, the antiferromagnetic insulating material being one of NiO and α-Fe 2 O 3 , and the second shielding layer is in contact with the pair of bias layers and the second insulating layer.  
     
     
       10. A thin-film magnetic head according to  claim 9 , wherein the pair of conductive layers is located on both sides in the track width direction of the nonmagnetic conductive layer, the pinned magnetic layer, and the antiferromagnetic layer, and the pair of conductive layers is in contact with the free magnetic layer. 
     
     
       11. A floating-type magnetic head comprising a slider and a thin-film magnetic head according to  claim 9 .